Compositions of urea formaldehyde particles and methods of making thereof

ABSTRACT

An improved composition comprising substantial spherical UFP particles and an active agent, such as NBPT, and optionally other components is used as an additive for liquid and solid fertilizers, typically containing urea. Methods of making the compositions and their use are also disclosed.

CROSS-REFERENCE

This application is a continuation-in-part of U.S. application Ser. No.14/671,337, filed Mar. 27, 2015, which is a continuation of U.S.application Ser. No. 13/968,330 filed Aug. 15, 2013, which claimspriority under 35 U.S.C. §119(e) from U.S. Provisional Application61/683,319, filed Aug. 15, 2012, the disclosures of each of theforegoing being incorporated herein by reference.

BACKGROUND OF THE INVENTION

Fertilizers have been used for some time to provide nitrogen to thesoil. Commercial fertilizers can come in a variety of liquid or solidforms. The most widely used and agriculturally important liquid form ofnitrogen fertilizer is urea ammonium nitrate (UAN) and the most widelyused and agriculturally important solid form is granular urea, a whitecrystalline solid under normal conditions. Urea is a commonly usednitrogen fertilizer due to its relatively low cost and its high nitrogenconcentration (46%). Solid forms of urea, include granular, prilled,pelletized, powdered or dust. Normally, the granular form is somewhatlarger in particle size than the prills. Most of the urea-basedfertilizer currently used is produced in its granular form.

After urea is applied to soil, it is hydrolyzed to yield ammonia andcarbon dioxide. This process is catalyzed by the enzyme urease, which isan extracellular enzyme in the soil. The gaseous products formed by thehydrolysis reaction (ammonia and carbon dioxide) volatilize to theatmosphere and thus, substantial losses from the total amount of thenitrogen applied to the field occur. Accordingly, some solid, watersoluble fertilizers can be made slow release by various additives. Forexample, the hydrolysis process can be considerably decelerated byapplying enzyme inhibitors, specifically urease or nitrificationinhibitors with urea. Examples of urease inhibitors are thethiophosphoric triamide compounds disclosed in the U.S. Pat. No.4,530,714, including N-(n-butyl)thiophosphoric triamide (NBPT). NBPT isused in a number of agricultural products, such as AGROTAIN® andAGROTAIN ULTRA® (see e.g. U.S. Pat. No. 5,698,003) and SUPER N® (seee.g. U.S. Pat. No. 5,364,438) and SUPER U®, UFLEXX® and UMAXX® (see e.g.U.S. Pat. No. 5,352,265).

Industrial grade N-(n-butyl)thiophosphoric triamide (NBPT) is a solid,waxy and sticky compound, that decomposes in water and at elevatedtemperatures. Accordingly, its direct application onto urea particles isvery difficult. In some applications, PERGOPAK® M by the AlbemarleCorporation (which is made by the process disclosed in U.S. Pat. No.6,936,078) has been used as a carrier for NBPT (see U.S. PatentPublication 2007/0157689). NBPT is deposited into the PERGOPAK® M byfirst dissolving the NBPT in NMP and then drying the NBPT and PERGOPAK®M mixture to form a solid. This solid is then blended with granulatedurea. An alternative form of this product can be made by applying themolten NBPT directly to the PERGOPAK® M and then subsequently blendingthis with granulated urea.

However, the combination of NBPT with PERGOPAK® M can result in severalproblems making its use difficult. The combination can form large clumpswhich must be filtered out before use. This leads to poor product yield.The combination can also have difficulty flowing through equipment,which leads to poor consistency of application levels on urea. Thecombination is also dusty and has an undesirable odor. These issues canlead to variations in NBPT ratios when formulating the mixture of NBPTand PERGOPAK® M with granulated urea. Because of variations in the NBPTlevels, formulators may need to add a significant excess of theNBPT/PERGOPAK® M formulation to form a commercial, granulated ureaformulation. In addition, there are also safety challenges in managingthe dust levels at formulation facilities. Further, the mixture of NBPTand PERGOPAK® M has limited long-term stability and can typically onlybe stored in containers smaller than or including a fiber drum in orderto minimize decomposition.

Accordingly, there remains a need for new compositions and methods ofimproving the properties of urea-based fertilizers that are coated on,embedded in, coated by, adhered with, commingled with, or otherwisecombined with other active agents. The present invention as describedherein addresses this and other needs by providing a formulation ofurease or nitrification inhibitors with a urea-formaldehyde polymer asdisclosed in U.S. Pat. No. 6,936,681. The formulation of the presentinvention significantly improves the flow of the mixture comprising theurease inhibitor, thereby reducing dust, increasing bulk density andproviding more uniform formulated product.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to a composition comprising an activeagent combined with particles of a different material. The presentinvention also relates to methods of making the compositions and theiruse in agricultural applications. At least one active agent ispreferably provided in the form of substantially solid pieces; however,active agents in liquid form may be included. Active agents can includeurease inhibitors and nitrification inhibitors. In particular,N-(n-butyl)thiophosphoric triamide (NBPT) can be used. The particles ofa different material can be particles of a material known foragricultural use and particularly can be particles of a materialsuitable for use as a fertilizer material, such as urea-formaldehydepolymer (UFP).

In some embodiments, the present invention can provide a compositioncomprising a combination of substantially solid pieces of N-(n-butyl)thiophosphoric triamide (NBPT) and urea-formaldehyde polymer (UFP)particles, wherein the pieces of NBPT and the UFP particles aresubstantially adhered together. In one or more further embodiments, thecompositions can be defined in relation to one or more of the followingstatements, which can be combined in any number or combination.

The UFP particles can be substantially adhered to outer surfaces of thepieces of NBPT.

The UFP particles can be substantially coating the pieces of NBPT.

The composition can comprise about 30% to about 70% by weight of thepieces of NBPT and about 70% to about 30% by weight of the UFP particlesbased on the total weight of the composition.

The composition further can comprise a nitrification inhibitor.

The nitrification inhibitor can be selected from the group consistingof: dicyandiamide (DCD); 2-chloro-6-trichloromethylpyridine(nitrapyrin); 3,4-dimethylpyrazole phosphate (DMPP); 3-methylpyrazole(MP); 1-H-1,2,4-triazole (TZ); 3-methylpyrazole-1-carboxamide (CMP);4-amino-1,2,4-triazole (AT, ATC); 3-amino-1,2,4-triazole;2-cyanimino-4-hydroxy-6-methylpyrimidine (CP); 2-ethylpyridine; ammoniumthiosulfate (ATS); sodium thiosulfate (ST); thiophosphoryl triamide;thiourea (TU); guanylthiourea (GTU); ammonium polycarboxylate; ethyleneurea; hydroquinone; phenylacetylene; phenylphosphoro diamidate;neemcake; calcium carbide; 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol(etridiazol, terraole); 2-amino-4-chloro-6-methylpyrimidine (AM);1-mercapto-1,2,4-triazole (MT); 2-mercaptobenzothiazole (MBT);2-sulfanilamidothiazole (ST); 5-amino-1,2,4-thiasiazole;2,4-diamino-6-trichloromethyl-s-triazine (CL-1580); N-2,5-dichlorophenylsuccinanilic acid (DCS); nitroaniline; chloroaniline; salts thereof; andcombinations thereof.

The nitrification inhibitor can be DCD.

The nitrification inhibitor can be nitrapyrin.

The composition can comprise about 1% to about 60% by weight of thepieces of NBPT, about 1% to about 35% by weight of the UFP particles,and about 5% to about 98% by weight of the nitrification inhibitor basedon the total weight of the composition.

The composition further can comprise a component selected from the groupconsisting of a conditioner, a dye, xanthan gum, and combinationsthereof.

The composition can comprise a conditioner selected from the groupconsisting of tricalcium phosphate, sodium bicarbonate, sodiumferricyanide, potassium ferricyanide, bone phosphate, sodium silicate,silicon dioxide, calcium silicate, talcum powder, bentonite, calciumaluminum silicate, stearic acid, sodium aluminosilicate, polyacrylatepowder, and combinations thereof.

The UFP particles can have an average particle diameter of about 0.05microns to about 250 microns.

The UFP particles can have an average particle diameter of about 0.1microns to about 150 microns.

The UFP particles can have a size distribution such that about 1% toabout 20% by weight of the UFP particles can have an average particlediameter of about 0.05 microns to about 5 microns.

About 1% to about 20% by weight of the UFP particles can have an averageparticle diameter of about 0.1 microns to about 1 micron, and about 80%to about 99% by weight of the UFP particles can have an average particlediameter that is greater than 1 micron.

The composition further can comprise urea.

The composition can comprise about 90% to about 99% by weight of ureaand about 0.02 to about 0.5% by weight of the pieces of NBPT based uponthe overall weight of the composition.

The composition comprising urea further can comprise a nitrificationinhibitor selected from the group consisting of: dicyandiamide (DCD);2-chloro-6-trichloromethylpyridine (nitrapyrin); 3,4-dimethylpyrazolephosphate (DMPP); 3-methylpyrazole (MP); 1-H-1,2,4-triazole (TZ);3-methylpyrazole-1-carboxamide (CMP); 4-amino-1,2,4-triazole (AT, ATC);3-amino-1,2,4-triazole; 2-cyanimino-4-hydroxy-6-methylpyrimidine (CP);2-ethylpyridine; ammonium thiosulfate (ATS); sodium thiosulfate (ST);thiophosphoryl triamide; thiourea (TU); guanylthiourea (GTU); ammoniumpolycarboxylate; ethylene urea; hydroquinone; phenylacetylene;phenylphosphoro diamidate; neemcake; calcium carbide;5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol (etridiazol, terraole);2-amino-4-chloro-6-methylpyrimidine (AM); 1-mercapto-1,2,4-triazole(MT); 2-mercaptobenzothiazole (MBT); 2-sulfanilamidothiazole (ST);5-amino-1,2,4-thiasiazole; 2,4-diamino-6-trichloromethyl-s-triazine(CL-1580); N-2,5-dichlorophenyl succinanilic acid (DCS); nitroaniline;chloroaniline; salts thereof; and combinations thereof.

The composition can be in the form of a granular fertilizer such thatthe granules of the fertilizer have an average diameter of about 0.8 toabout 4.8 millimeters.

The composition further can comprise an aqueous solution of ureaammonium nitrate (UAN).

The composition can comprise about 24% to about 32% by weight of urea,about 34% to about 42% by weight of ammonium nitrate, and about 0.01% toabout 0.4% by weight of the pieces of NBPT based on the overall weightof the composition.

The composition comprising urea and ammonium nitrate further cancomprise a nitrification inhibitor selected from the group consistingof: dicyandiamide (DCD); 2-chloro-6-trichloromethylpyridine(nitrapyrin); 3,4-dimethylpyrazole phosphate (DMPP); 3-methylpyrazole(MP); 1-H-1,2,4-triazole (TZ); 3-methylpyrazole-1-carboxamide (CMP);4-amino-1,2,4-triazole (AT, ATC); 3-amino-1,2,4-triazole;2-cyanimino-4-hydroxy-6-methylpyrimidine (CP); 2-ethylpyridine; ammoniumthiosulfate (ATS); sodium thiosulfate (ST); thiophosphoryl triamide;thiourea (TU); guanylthiourea (GTU); ammonium polycarboxylate; ethyleneurea; hydroquinone; phenylacetylene; phenylphosphoro diamidate;neemcake; calcium carbide; 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol(etridiazol, terraole); 2-amino-4-chloro-6-methylpyrimidine (AM);1-mercapto-1,2,4-triazole (MT); 2-mercaptobenzothiazole (MBT);2-sulfanilamidothiazole (ST); 5-amino-1,2,4-thiasiazole;2,4-diamino-6-trichloromethyl-s-triazine (CL-1580); N-2,5-dichlorophenylsuccinanilic acid (DCS); nitroaniline; chloroaniline; salts thereof; andcombinations thereof.

The composition comprising urea and ammonium nitrate can comprise about0.01% to about 2.0% by weight of the nitrification inhibitor based onthe overall weight of the composition.

The pieces of NBPT can comprise crystalline NBPT.

The pieces of NBPT can comprise amorphous NBPT.

In one or more embodiments, the present disclosure can provide a methodof forming an agricultural composition. For example, the method cancomprise blending substantially solid pieces of N-(n-butyl)thiophosphoric triamide (NBPT) with urea-formaldehyde polymer (UFP)particles under conditions such that the UFP particles becomesubstantially adhered to outer surfaces of the pieces of NBPT.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a 1000× magnification photograph showing the morphology ofparticles comprising PERGOPAK® M and NBPT according to one or moreembodiments of the present invention;

FIG. 1B is a 1000× magnification photograph showing the morphology ofparticles comprising NITAMIN 36S and NBPT according to one or moreembodiments of the present invention;

FIG. 2a is an optical image (200× magnification) of substantially solidpieces of NBPT combined with UFP particles according to one or moreembodiments of the invention such that the UFP particles are adhered tothe outer surfaces of the NBPT pieces;

FIG. 2b is an optical image (500× magnification) of the combined NBPTand UFP of FIG. 2 a.

DETAILED DESCRIPTION OF THE INVENTION

The invention can relate to the combination of certain particles with anactive agent, which active agent particularly can be in a solid form. Inone embodiment, the composition comprises from about 30% to 70% of anactive agent and from about 70% to about 30% by weight of particles of adifferent material based on the total weight of the composition, whichparticles particularly can be particles of a urea-formaldehyde polymer,for example, substantially spherical UFP particles.

All percentages, parts and ratios are based upon the total weight of thecompositions of the present invention, unless otherwise specified. Allsuch weights as they pertain to listed ingredients are based on theactive level and, therefore, do not include solvents or by-products thatmay be included in commercially available materials, unless otherwisespecified. The term “weight percent” may be denoted as “wt. %” herein.All molecular weights as used herein are weight average molecularweights expressed as grams/mole, unless otherwise specified.

As used herein, “substantially” is intended to indicate a range of up toabout 20% of any value indicated.

The term “substantially spherical” as used herein means that thematerial has a morphology that includes spherical, as well as oblong,and the like and can have surface irregularities. The sphericity of aparticle can be determined using image analyzer which identifies andmeasures a particles image in the form of a sphere, and calculates thesphericity of a particle, as Da/Dp (where Da=(4 A/π); Dp=P/π; A=pixelarea; P=pixel perimeter), is a value from zero to one, with onerepresenting a sphere. For example, in some embodiments, the particlecan have a sphericity of about 0.8 or more, about 0.81 or more, about0.82 or more, about 0.83 or more, about 0.84 or more, about 0.85 ormore, about 0.86 or more, about 0.87 or more, about 0.88 or more, about0.89 or more, about 0.9 or more, about 0.91 or more, about 0.92 or more,about 0.93 or more, about 0.94 or more, about 0.95 or more, about 0.96or more, about 0.97 or more, about 0.98 or more, or about 0.99 or more.

The particles that are combined with the active agent can particularlybe UFP particles and, more particularly, can be substantially sphericalUFP particles. For example, substantially spherical UFP particles thatare useful according to some embodiments of the present invention arethose disclosed in U.S. Pat. No. 6,936,681, which is incorporated in itsentirety herein by reference. Non-limiting examples of urea-formaldehydepolymers suitable for use in the practice of the present include thosesold under the name NITAMIN 36S® by Koch Agronomic Services, LLC.

Substantially spherical UFP particles can be prepared by reacting, in anaqueous environment, urea and formaldehyde at a urea:formaldehyde moleratio of about 1:1. To prepare the UFP particles, urea and formaldehydeare reacted in admixture at a mole ratio of approximately 1:1, forexample at a UF mol. ratio broadly in the range of 0.7:1≦U:F≦1.25:1 andor in the range of 0.83:1≦U:F≦1.1:1. The phase “at a mole ratio ofapproximately 1:1” is intended to embrace these mole ratio ranges.Particularly good results have been obtained at a U:F mole ratio between0.95:1 and 1.05:1.

In the initial step of preparing the substantially spherical UFPparticles, reaction between urea and formaldehyde is conducted in amanner to produce methylol ureas. For example, reaction between the ureaand formaldehyde can be promoted by maintaining the aqueous mixtureinitially at a moderate alkaline pH, with a pH in the range of about 7to 9 being suitable and with a pH more usually between about 7.5 and8.5, to promote the formation of methylol ureas. Given urea's inherentlevel of alkalinity, any required pH adjustment may be accomplishedusing either an acid or a base. The initial formation of methyol ureasgenerally can be conducted at a reaction temperature broadly in therange of 70° F. to 175° F. (about 20° C. to about 80° C.) with areaction temperature in the range of 90° F. to 160° F. (about 30° C. toabout 70° C.) more usually employed. The pH may be adjusted usingcommonly available acids and bases such as sodium hydroxide (caustic)and sulfuric acid and any material that can alter the pH is suitable forthis purpose. The reaction pH also may be maintained (buffered) oradjusted by adding such alkaline compounds as triethanolamine, sodium orpotassium bicarbonate, sodium or potassium carbonate, or other alkalimetal hydroxides, such as potassium hydroxide and lithium hydroxide.Alternatively, the methylolation may also be done at a moderate acidicpH, such as in the pH range of 5.0 to 6.0, as will be recognized bythose skilled in the art and the present invention is not limited by theway the initial methylolation is conducted.

Following the initial formation of methylol ureas, the nascent UFP thenis condensed to the point where the polymer becomes insoluble in theaqueous environment. This result can be accomplished by rapidlyacidifying the methylol ureas, to a pH below about 6, usually belowabout 5 and usually to a pH below about 4, but above about 1. A pH inthe range of 2.5 to 4.0 has proven to be suitable. Any organic orinorganic acid that will lower the pH can be used. Particularly suitableis a strong acid, such as a mineral acid and an organic acid such as thestronger carboxylic acids. Thus, suitable acids include formic acid,acetic acid, nitric acid, phosphoric acid, sulfuric acid andhydrochloric acid. However, in its broadest aspects the presentinvention is not limited by the way the further polymerization of themethylol ureas and ultimate insolubilization is conducted and obtained.

In order to produce a desired range of substantially spherical UFPparticle diameters, the aqueous mixture of the methylol ureas is mixedin the presence of a dispersing agent during the step of rapidpolymerization which leads to insolubilization, such as the rapidacidification step, although it is possible to get a similar result bymaintaining a sufficiently high level of agitation (high shear) duringthe reaction in the absence of any dispersing agent. The resultingdispersion of UFP formed from the polymerization that occurs, forexample, following acidification, is then recovered or isolated from thedispersion to produce substantially spherical UFP particles, which thenare used in any of the various applications noted herein. Thesubstantially spherical UFP particles formed in this manner haveapproximately 36% by weight nitrogen when dry.

Skilled practitioners recognize that the formaldehyde and urea reactantsused to make the substantially spherical UFP particles of this inventionare commercially available. The formaldehyde used can be in anyavailable form. Paraform (solid, polymerized formaldehyde) and formalinsolutions (aqueous solutions of formaldehyde, sometimes with methanol,in 37 percent, 44 percent, or 50 percent formaldehyde concentrations)are commonly used sources of formaldehyde. Formaldehyde also may beavailable as a gas. Each of these sources of formaldehyde is suitablefor use in the preparing the substantially spherical UFP particles ofthis invention. Generally, for ease of use, formalin solutions are usedas the formaldehyde source. In addition, some of the formaldehyde may bereplaced with another aldehyde, such as acetaldehyde and/orpropylaldehyde that can react with urea. Glyoxal may also be used inplace of formaldehyde, as may other aldehydes not specificallyenumerated.

Urea also is available in many forms. Solid urea, such as prill, andurea solutions, typically aqueous solutions, are commercially available.Further, urea often is chemically combined with formaldehyde in the formof a urea-formaldehyde concentrate, such as UFC 85, or as acommercially-available solution containing about 25 weight percent urea,about 60 weight percent formaldehyde, and about 15 weight percent water,available under the trademark STA-FORM 60®. In one embodiment the ureaformaldehyde source is UFC 85. Each of these sources of urea andformaldehyde can be used in preparing the substantially spherical UFPparticles of this invention.

The urea-formaldehyde condensation reaction that results in thesubstantially spherical UFP particles of this invention may be conductedin an aqueous environment. As noted above, the reaction is conducteduntil the growing urea-formaldehyde polymer becomes insoluble in theaqueous reaction medium. A dispersing agent may be included in the waterto facilitate the production of small polymer particles by the reaction.One suitable dispersant is the line of DAXAD® dispersants commerciallyavailable from Hampshire Chemicals, a subsidiary of the Dow ChemicalCompany. One of the classes of these dispersants is a condensednaphthalene sulfonate. Both the high and low molecular weight species ofthis product line have been shown to be suitable, such as DAXAD 19. Avariety of other dispersants or surfactants also can be used, includingthose that might be classified as anionic, such as polyacrylates (alsoavailable under the DAXAD® label-such as DAXAD 30 from HampshireChemicals). Nonionic and cationic dispersant compounds also can be used.The nature of the specific dispersant/surfactant is not critical.Another example is a lignosulfonate salt or lignin. It is also possibleto dispense with the use of any dispersant, provided that the reactionmedium is sufficiently agitated (high shear) during the UF condensationreaction to promote the formation of small substantially spherical UFPparticles.

The amount of dispersant to include in the aqueous solution of methylolurea at the time of the insolubilization reaction can be readilydetermined by those skilled in the art. The amount depends to someextent on the particular dispersant chosen to use and the concentrationof methylol urea in the aqueous reaction medium. Generally, the urea andformaldehyde reactants and the water vehicle are provided in amounts toyield a methylol urea concentration that ultimately provides adispersion of UFP at about a 20% by weight solid concentration up toabout 60% by weight solids. More usually, the materials are provided sothat the UFP dispersion is between about 30% and 55% by weight solids.In one embodiment, the dispersion UFP is prepared at about a 40% byweight solids concentration. Under these conditions, the dispersingagent is generally supplied at a concentration of between about 0.1% and5% by weight, and usually in at least about 0.5% by weight up to about2% by weight.

In the broad practice of this invention, the aqueous dispersion of UFPis isolated to form substantially spherical UFP particles before use.According to the broadest aspects of the invention, any way forisolating the substantially spherical UFP particles from the aqueoussubstantially spherical UFP particles dispersion can be used. Forexample, the substantially spherical UFP particles in the dispersion maybe isolated by filtration and oven drying, or by thin film evaporation.When using these latter techniques, it may then be necessary to reducethe particle diameter of the recovered solids, for example by grinding,to obtain a desired particle diameter or diameter distribution for aspecific application.

In one embodiment, the way of isolating or recovering the substantiallyspherical UFP particles from the dispersion formed by the polymerizationof urea and formaldehyde as described above, is by spray-drying. As usedherein, the terms “spray dryer” and “spray drying” refer to thetechnically sophisticated process of atomizing (in the form of finelydivided droplets) the UFP dispersion or slurry into a gas stream (oftena heated air stream) under controlled temperature conditions and underspecific gas/liquid contacting conditions to effect evaporation of waterfrom the atomized droplets and production of a dry particulate solidproduct. Spray drying as used herein is typically carried out withpressure nozzles (nozzle atomization) or centrifugal atomizers operatingat high speeds (e.g., a spinning disc). Despite the high velocitygeneration of droplets, a spray dryer is designed so that the dropletsdo not contact the spray dryer wall under proper operating procedures.This effect is achieved by a precise balance of atomizer velocity, airflow, spray dryer dimensions of height and diameter, and inlet andoutlet means to produce a cyclonic flow of gas, e.g., air in thechamber. A pulse atomizer also can be used to produce the small dropletsneeded to facilitate evaporation of the water. In some cases, it may bedesirable to include a flow promoter, such as an aluminosilicatematerial, in the aqueous dispersion that is processed in a spray dryersimply to facilitate subsequent handling and transport of the spraydried substantially spherical UFP particles (e.g., to avoid clumping).

The shape and size of the substantially spherical UFP particles isfairly consistent. Producing substantially spherical UFP particles of aconsistent size helps adhere the desired amount of active as well asother components subsequent formulations. By using the method of makingthe substantially spherical UFP particles in the presence of adispersant, it is easy to produce most of the substantially sphericalUFP particles of a consistent size so as to pass through a 100 mesh(U.S. or Tyler) screen, and generally at least a major portion passthrough a 200 mesh screen. Thus, the majority of the substantiallyspherical UFP particles with have a diameter larger than about 0.15micrometers.

UFP particles used according to the present invention, whethersubstantially spherical UFP particles or not, preferably can have anaverage diameter that can be defined by one or more sets of ranges. Forexample, in one or more embodiments, UFP particles can have an averagediameter of about 0.05 microns to about 250 microns, about 0.1 micronsto about 150 microns, or about 0.2 microns to about 100 microns.Preferably, about 50% or greater, about 75% or greater, about 80% orgreater, about 85% or greater, about 90% or greater, about 95% orgreater, about 98% or greater, or about 99% or greater by weight of theparticles will have an average diameter falling within one or more ofthe above ranges, said weight being relative to the total weight of theparticles. If desired, particles falling within two or more differentsize ranges can be used.

In some embodiments, at least a portion of the particles can have anaverage diameter in a first size range. For example, a lower size rangecan be about 0.01 microns to about 50 microns, about 0.02 microns toabout 25 microns, about 0.03 microns to about 20 microns, about 0.04microns to about 10 microns, about 0.05 microns to about 5 microns,about 0.07 microns to about 2 microns, or about 0.1 microns to about 1microns. In particular about 0.1% to about 50%, about 0.2% to about 30%,about 0.5% to about 25%, about 1% to about 20%, or about 2% to about 15%by weight of the particles will have an average diameter falling withinone or more of the above ranges, said weight being relative to the totalweight of the particles.

In some embodiments, at least a portion of the particles can have anaverage diameter in a second size range. For example, a second sizerange can be about 5 microns to about 250 microns, about 10 microns toabout 150 microns, or about 10 microns to about 100 microns. Inparticular, about 5% to about 99%, about 10% to about 95%, about 15% toabout 90%, or about 20% to about 85% by weight of the particles willhave an average diameter falling within one or more of the above ranges,said weight being relative to the total weight of the particles.

In some embodiments, at least a portion of the particles can have anaverage diameter that is up to a threshold value, and at least a portionof the particles can have an average diameter that is greater than thethreshold value. The threshold value can be 0.5 microns, 1 micron, 2microns, 5 microns, or 10 microns. About 0.1% to about 40%, about 0.5%to about 30%, about 1% to about 20%, about 2% to about 15%, or about 5%to about 10% by weight of the particles can have an average diameterthat is up to the threshold value, said weight being relative to thetotal weight of the particles. About 50% to about 99%, about 60% toabout 99%, about 70% to about 99%, about 80% to about 99%, about 85% toabout 99%, or about 90% to about 99% by weight of the particles can havean average diameter that is greater than the threshold value, saidweight being relative to the total weight of the particles.

The term “majority” as used herein means the greater number or part; anumber more than half the total. For example, in some embodiments,majority can mean about 51% or more, about 52% or more, about 53% ormore, about 54% or more, about 55% or more, about 56% or more, about 57%or more, about 58% or more, about 59% or more, about 60% or more, about61% or more, about 62% or more, about 63% or more, about 64% or more,about 65% or more, about 66% or more, about 67% or more, about 68% ormore, about 69% or more, about 70% or more, about 71% or more, about 72%or more, about 73% or more, about 74% or more, about 75% or more, about76% or more, about 77% or more, about 78% or more, about 79% or more,about 80% or more, about 81% or more, about 82% or more, about 83% ormore, about 84% or more, about 85% or more, about 86% or more, about 87%or more, about 88% or more, about 89% or more, about 90% or more, about91% or more, about 92% or more, about 93% or more, about 94% or more,about 95% or more, about 96% or more, about 97% or more, about 98% ormore, about 99% or more.

Thus, in the broad practice of this invention, the isolated,substantially spherical UFP particles, recovered from the aqueousdispersion, for example by spray-drying, then is used in combinationwith active agents and in further applications.

While not wishing to be bound by theory, the inventors hereof believemorphology of the substantially spherical UFP particles is directlyattributable to the conditions of the above-process. Also, the inventorsbelieve morphology of the substantially spherical UFP particles not onlyfacilitates its combination with the active agent(s) but also improvesthe properties of further formulations. Because of its uniformity insize and shape, the composition of the substantially spherical UFPparticles has significantly less dust which avoids the need for furtherdust control agents, which can cause undesirable properties, such asclumping in subsequent formulations.

Although the foregoing description particularly relates to substantiallyspherical UFP particles, it is understood that the present invention isnot necessarily limited to the use of only substantially spherical UFPparticles. Rather, particles used herein for combination with an activeagent can be UFP that is not substantially spherical, or can beparticles of a material other than UFP (said other particles beingsubstantially spherical or not). Specific discussion of substantiallyspherical UFP particles is provided herein in relation to certainpreferred embodiments, and it will be recognized that specific relationto substantially spherical UFP particles is utilized to describe themethods of making such particles and matters related to the specific usethereof. For ease of discussion, general disclosure herein may relate toUFP particles that can be combined with an active agent. Such generaldiscussion is understood to encompass the use of substantially sphericalUFP particles, as well as the use of particles that are formed of adifferent material and that may or may not be substantially spherical.Such general usage is intended for the sake of consistency throughoutthe disclosure and is not mean to limit the invention.

“Active agent” as used herein is meant to refer to compounds, chemicals,etc., that finds use in agricultural applications and are commonlyapplied to urea-formaldehyde polymers. Non-limiting examples of activeagents suitable for use herein include materials commonly used infertilizer applications that are not toxic to seeds, or harmful to thesoil environment in which seeds are planted, or in which a plant isgrowing. Such materials may include urease or nitrification inhibitors,pesticides, herbicides and fungicides to combat or prevent undesiredinsects, weeds and disease. Mixtures of these different materials may ofcourse also be employed. In one group of embodiments, described in moredetail hereafter, one or more of these materials is combined with thesubstantially spherical UFP particles of the invention to producegranular fertilizer solids.

In one group of embodiments of the invention, the UFP particles are usedwith one or more of a urease inhibitor, a nitrification inhibitor, and apesticide, such as a fungicide, an insecticide, or a herbicide. Ureaseinhibitor, as used herein, is meant to refer to compounds that interferewith urease activity and reduce urea hydrolysis in soils. In one groupof embodiments the active agent is a urease inhibitor. Examples ofurease inhibitors include, but are not limited to, phosphoric triamides,such as N-(n-butyl)thiophosphoric triamide (NBPT) and the like. Inanother group of embodiments, the urease inhibitor isN-(n-butyl)thiophosphoric triamide (“NBPT”). The NBPT can be crude orpure (with less than 10% other ingredients). In some embodiments, theNBPT is purified by recrystallization.

In one or more embodiments, NBPT for combination with UFP particles canbe in the form of substantially solid pieces. Substantially solid piecesof NBPT are understood to refer to NBPT provided as discrete units(i.e., “pieces”) that can vary in size and/or shape and can be regularlyshaped or irregularly shaped. The pieces are substantially solid in thatthey may be softened at the surface, through a potion of the piece, orcompletely throughout, but the pieces are not liquefied or flowable, andthe pieces substantially retain their shape absent applied force. Suchdescription can apply to the substantially solid pieces of NBPT atambient conditions and/or under conditions wherein the NBPT is combinedwith the UFP particles. Substantially solid pieces of NBPT are expresslydistinguishable from NBPT in a flowable state (such as further describedherein) in relation to embodiments wherein the NBPT may be substantiallyliquefied so as to be provide as a coating on the UFP particles.

The NBPT used herein may be in a substantially crystalline form. In someembodiments, however, the NBPT may be in an amorphous form. If desired,the NBPT can comprise crystalline NBPT and amorphous NBPT in mixturesranging from 1% by weight to 99% by weight crystalline NBPT and 99% byweight to 1% by weight amorphous NBPT, based on the total weight of theNBPT combined with the UFP particles. In one or more embodiments, theratio of crystalline NBPT to amorphous NBPT can be about 5:95 to about95:, about 10:90 to about 90:10, about 20:80 to about 80:20, bout 30:70to about 70:30, about 40:60 to about 60:40, or about 45:55 to about5:45. In some embodiments, the crystalline NBPT can be about 50% byweight to about 99.9% by weight, about 60% to about 99.8% by weight,about 70% to about 99.5% by weight, about 80% to about 99.5% by weight,about 85% by weight to about 99% by weight, or about 90% by weight toabout 98% by weight of the total amount of NBPT combined with the UFPparticles. The NBPT pieces thus may be referred to as crystals of NBPTor substantially solid crystals of NBPT, and such designations can beconsidered to include NBPT that is up to 5%, up to 4%, up to 3%, up to2%, up to 1.5%, up to 1%, up to 0.5%, or up to 0.1% by weight amorphousNBPT. In some embodiments, the form of the NBPT may be referenced apartfrom the crystalline nature thereof. Thus, NBPT pieces can encompassNBPT particles or NBPT units (which particles or units can becrystalline and/or amorphous in nature).

Nitrification inhibitors are compounds which inhibit the conversion ofammonium to nitrate and reduce nitrogen losses in the soil. Examples ofnitrification inhibitors include, but are not limited to, dicyandiamide(DCD); 2-chloro-6-trichloromethylpyridine (nitrapyrin);3,4-dimethylpyrazole phosphate (DMPP); 3-methylpyrazole (MP);1-H-1,2,4-triazole (TZ); 3-methylpyrazole-1-carboxamide (CMP);4-amino-1,2,4-triazole (AT, ATC); 3-amino-1,2,4-triazole;2-cyanimino-4-hydroxy-6-methylpyrimidine (CP); 2-ethylpyridine; ammoniumthiosulfate (ATS); sodium thiosulfate (ST); thiophosphoryl triamide;thiourea (TU); guanylthiourea (GTU); ammonium polycarboxylate; ethyleneurea; hydroquinone; phenylacetylene; phenylphosphoro diamidate;neemcake; calcium carbide; 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol(etridiazol, terraole); 2-amino-4-chloro-6-methylpyrimidine (AM);1-mercapto-1,2,4-triazole (MT); 2-mercaptobenzothiazole (MBT);2-sulfanilamidothiazole (ST); 5-amino-1,2,4-thiasiazole;2,4-diamino-6-trichloromethyl-s-triazine (CL-1580); N-2,5-dichlorophenylsuccinanilic acid (DCS); nitroaniline; chloroaniline; salts thereof; andcombinations thereof.

In one or more embodiments, a nitrification used herein particularly caninclude DCD. The DCD of the present invention can have a particle sizein the range from about 50 to 350 μm. The DCD is present in the dryflowable additive in the range of about 0.01 to 99%, or about 40 to 95%,or 70 to 90%. In a further embodiment of the invention, the dry flowableadditive may contain from about 1.0 to 30.0% substantially spherical UFPparticles and from about 40 to 90% DCD. Without DCD, the composition maycontain about 1 to 80% NBPT and about 99 to 20% of the substantiallyspherical UFP particles. The ratio of NBPT to DCD should exceed a valueof about 0.02, in some embodiments is be between about 0.02 and about10.0, and in some embodiments is between about 0.04 and about 4.0. Inone embodiment the composition comprises about 81% DCD, about 8% UFP,and about 11% of a NBPT/UFP mixture. In some embodiments only one activeagent, as described above, is used. While the foregoing (and furtherdiscussion herein) may relate to DCD specifically, it is understood thatsuch discussion does not necessarily exclude the use of one or moredifferent nitrification inhibitors, such as the further examples of suchmaterials described above.

The utilization of both a urease inhibitor and a nitrificationinhibitor, in the fertilizer composition of this invention offers anopportunity to tailor the make-up of the composition to match thenitrogen nutrient demand of a given crop/soil/weather scenario. Forexample, if the soil is characterized by a low pH and/or if rain isanticipated shortly after fertilizer application and the opportunity forammonia losses through volatilization to the atmosphere is therebydiminished, the level of the NBPT urease inhibitor incorporated into theformulation may be reduced, within the specified range, without alsochanging the level of the DCD (nitrification inhibitor). The relativeresistance of the fluid fertilizer composition of this invention to ureahydrolysis and ammonia oxidation is controlled by properly selecting theNBPT to DCD weight ratio of the composition. This ratio should exceed avalue of about 0.01, or between about 0.02 and about 8.0, or be betweenabout 0.05 and about 1.0. Fluid fertilizer compositions with NBPT to DCDweight ratios near the higher end of these ranges will exhibitrelatively higher resistance to urea hydrolysis than to ammoniumoxidation, and vice versa. This independent control over the relativeresistance of the composition to urea hydrolysis and ammonia oxidationis unattainable through the methods of prior art and providesunparalleled flexibility in meeting the nutrient demands of variouscrops under a broad range of soil/weather conditions.

The means by which the one or more active agents are combined with theUFP particles can be selected from any method known. In one group ofembodiments, the one or more active agents are deposited onto the UFPparticles by using a blending or drying device such as a high shearmixer, ribbon blender, blade mixer, or other similar device. While heatneed not be applied during blending, in one group of embodiments, thedrying device is a ribbon blender or blade blender. In otherembodiments, the composition is blended in standard blending equipmentwithout drying equipment.

One or more active agents are combined with UFP particles by introducinginto the drying or blending device the particles and a solutioncomprising a solvent and the one or more active agents. The UFPparticles alternatively may be blended with the active ingredient(s)without solvent present. In another embodiment, molten NBPT is directlysprayed onto the UFP particles while mixing. The mixture is thensubsequently dried at an elevated temperature. As such, in someembodiments, the active agent and the UFP particles are combined suchthat the active agent is coated on the UFP particles, the active agentis embedded in the UFP particles, the active agent is smeared on the UFPparticles, or the like. In one or more embodiments, the pieces of theactive agent and the UFP particles are combined such that the UFPparticles are coated on the pieces of the active agent or the UFPparticles are embedded in the pieces of the active agent pieces. Thus,the active agent and the UFP particles can be comingled, admixed,homogenized, adhered, or otherwise combined to form a combinatoryproduct.

As seen in FIG. 1A and FIG. 1B, the surface morphology of combinationsof NBPT and UFP can vary based upon the nature of the UFP material withwhich the NBPT is combined. In some embodiments, the combination ofsubstantially solid pieces of NBPT with UFP particles can be such thatthe UFP particles are substantially adhered to surfaces of the pieces ofthe NBPT. As seen in the optical images of FIG. 2a and FIG. 2b , mixingof substantially solid pieces of NBPT 10 (e.g., NBPT crystals in theillustrated embodiment) with UFP particles 20 can result in the UFPparticles being applied to the surfaces of the pieces of the NBPT. Suchapplication can be via a number of forces, including adhesion forces. Inparticular, the UFP particles can be substantially embedded in thesurfaces of the pieces of the NBPT or adhered on the surfaces of theNBPT.

The amount of UFP particles used with any particular urease inhibitormay vary and will usually depend on the particular application, as wellas the optional presence of other components besides the UFP particlesused in the present invention. The composition comprising the one ormore active agents typically contains from about 30 to about 80 wt. % ofthe active agent, based on the weight of the composition, of the one ormore active agent(s). In one group of embodiments, the compositioncomprises from about 40 to 70 wt. %, based on the total weight of thecomposition. In one group of embodiments, the composition comprises fromabout 50 to about 60 wt. % of the active agent based on the total weightof the composition.

In the practice of this embodiment of the present invention, the UFPparticles and active agent solution can be introduced into the dryingdevice simultaneously, in stages, either the UFP particle solutionintroduced before the other, or any combinations thereof. Thus, thisembodiment of the present invention can be either a batch or continuousprocess. In one group of embodiments, the active agent solution isintroduced into the drying device after the UFP particles. In this andother embodiments, the introduction of the active agent solution iscontrolled to avoid over-wetting of the UFP particles. Over-wetting canbe prevented by introducing the active agent solution into the dryingdevice at a rate substantially equal to the rate at which the solventvolatilizes. The volatilization of the solvent is achieved by operatingthe drying device under conditions that include a temperature that isbelow the melting point of the active agent(s) and below the boilingpoint of the solvent. In one group of embodiments, the drying device isoperated under such a temperature and a sub-atmospheric pressure. In onegroup of embodiments, the temperatures under which the drying device isoperated are in the range of from about 20° C. to about 200° C., or inthe range of from about 20° C. to about 100° C., or from about 20° C. toabout 50° C. Also, as stated above, the drying device may be operatedunder sub-atmospheric pressures, i.e. under a vacuum. These pressuresmay be in the range of from about 760 mmHg to about 0.1 mmHg, or in therange of from about 500 mmHg to about 50 mmHg, or from about 100 mmHg toabout 50 mmHg.

Other optional components may be used in compositions of the presentinvention. Examples of other agents, include but are not limited to aconditioner, xanthan gum, calcium carbonate (agricultural lime) in itsvarious forms for adding weight and/or raising the pH of acid soils;metal containing compounds and minerals such as gypsum, metal silicatesand chelates of various micronutrient metals such as iron, zinc andmanganese; talc; elemental sulfur; activated carbon, which may act as a“safener” to protect against potentially harmful chemicals in the soil;a plant protectant; a nutrient stabilizer, super absorbent polymers,wicking agents, wetting agents, plant stimulants to accelerate growth,an inorganic nitrogen, phosphorus, potassium (N—P—K) type fertilizer,sources of phosphorus, sources of potassium, and organic fertilizers,surfactants, initiators, stabilizers, cross linkers, antioxidants, UVstabilizers, reducing agents, dyes, such as blue dye (FD & C blue #1);and plasticizers. Examples of conditioners include but are not limitedto tricalcium phosphate, sodium bicarbonate, sodium ferricyanide,potassium ferricyanide, bone phosphate, sodium silicate, silicondioxide, calcium silicate, talcum powder, bentonite, calcium aluminumsilicate, stearic acid, and polyacrylate powder. Examples of plantprotectants and nutrient stabilizers include silicon dioxide, and thelike.

The content of the additional components can be from about 1 to about 99percent by weight of the composition. For example, the amount of theadditional components in the composition can be about 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,98 or about 99% by weight of the total granular fertilizer composition.

The urea-based granular fertilizer of the present invention can includeany suitable quantity of a urea source and contains one or moreadditional components. In one group of embodiments, the urea source isgranulated solid or prilled urea. One of skill in the art willappreciate other urea sources for the inventive methods. The amount ofthe urea source in the urea-based granular fertilizer can range fromabout 1% to about 99% by weight of the total granular fertilizercomposition. The amount of the urea source in the urea-based granularfertilizer can be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68,69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 or about 99% by weight ofthe total granular fertilizer composition

In other embodiments, the invention provides a urea-based granularfertilizer composition comprising: a) a urea source of from about 95% to99% by weight of the total granular fertilizer composition; b) acomposition of an active agent and UFP particles as described above inthe range of from about 1% to 5% by weight of the total granularfertilizer composition.

Thus in one embodiment, the urea content of the composition of thisinvention is about 90% to about 99% by weight, and alternatively about92% to about 99% by weight. The content of the NBPT and substantiallyspherical UFP particle composition is about 0.02% to about 0.5% byweight, or about 0.04% to about 0.4% by weight. DCD may account forabout 0.01% to about 90% by weight of the composition, and in someembodiment's accounts for about 0.05% to about 81% by weight of thecomposition. The composition may also contain some moisture, ureasynthesis byproducts, and an NBPT solvent of this invention, and asnoted above may optionally contain other additives, such as a dye, anNBPT stabilizer, or a micronutrient. The diameter of the granules of theimproved homogenous urea-based fertilizer composition of this inventionranges from about 0.5 millimeters to about 10 millimeters, and in someembodiments from about 0.8 millimeters to about 0.9, to about 1.0, toabout 1.1, to about 1.2, to about 1.3, to about 1.4, to about 1.5, toabout 1.6, to about 1.7, to about 1.8, to about 1.9, to about 2.0, toabout 2.1, to about 2.2, to about 2.3, to about 2.4, to about 2.5, toabout 2.6, to about 2.7, to about 2.8, to about 2.9, to about 3.0, toabout 3.1, to about 3.2, to about 3.3, to about 3.4, to about 3.5, toabout 3.6, to about 3.7, to about 3.8, to about 3.9, to about 4.0, toabout 4.1, to about 4.2, to about 4.3, to about 4.4, to about 4.5, toabout 4.6, to about 4.7, and to about 4.8 millimeters.

In one aspect, the invention provides a method, wherein the contactingis selected from the group of blending and mixing. The conditioner whenmixed or blended with a urea-based fertilizer provides a urea-basedfertilizer that has improved storage and handling properties.

In one group of embodiments, the present invention provides acomposition similar to wherein commercial fertilizers, including, butnot limited to SUPER U®; UFLEXX®; UMAXX®; or granular urea treated withAGROTAIN DRY®, except that substantially spherical UFP particles areused as the UFP component.

In one group of embodiments, the NBPT/UFP particle composition can beincorporated into the homogenous urea-based fertilizer composition byblending, either dry or as a concentrated solution of NBPT/UFP in asolvent directly on urea. The incorporation can be done at ambientconditions or on molten urea at a temperature of about 266° F. to about275° F. prior to the granulation or prilling of the urea in aconventional urea production facility. Sufficient mixing is employedduring this blending step to assure that the NBPT/UFP solution ishomogeneously distributed, especially before the melt cools andsolidifies in the subsequent granulation step if molten urea is used.

The amount of the active agent and UFP particle compositions of thepresent invention added to urea in accordance with this invention ineither solid or liquid form depends on the desired NBPT content of thegranular fertilizer composition and can be readily calculated by thoseskilled in the art. In some embodiments, no or only very limitedquantities of a solvent are introduced into the urea along with the NBPTand UFP particle composition. For example, if the NBPT and UFP particlecomposition content of the concentrated NBPT solution used toincorporate the NBPT and UFP particle composition in the fertilizercomposition is 70% and the NBPT content of the resulting fertilizercomposition is 0.07%.

In some embodiments, DCD can be added to and blended with the urea atthis point in the formulation rather than during the formulation withUFP particles, alone. Several methods can be used for the introductionof DCD into solid or molten urea: if available as a powder or ingranular form, the DCD can be fed into a stream of solid or molten ureausing a conventional solids feeding device; or, the DCD may be dissolvedin a relatively small quantity of molten urea, as for example in a sidestream of molten urea in a urea plant, to form a concentrated DCDsolution in molten urea which is then metered into the main stream ofthe solid or molten urea. Finally, the DCD may be incorporated into asolution of the NBPT and UFP particle composition described hereinaboveand introduced into the urea or molten urea along with the NBPT and UFPparticle composition. Regardless of the method selected to introduce theDCD into the urea, sufficient mixing should be provided to facilitatehomogenous distribution of the DCD throughout the urea. The homogeneousdistribution of the NBPT, the UFP particle and DCD in the granularfertilizer compositions of this invention enhances the performance ofthese compositions in terms of their ability to promote plant growth.

The order in which the NBPT and UFP particle composition and the DCD areadded to the urea in the practice of this invention is flexible: eitherthe NBPT and UFP particle composition or DCD may be introduced first, orboth of these components may be added simultaneously. In one group ofembodiments, the DCD is added first to provide adequate time for boththe dissolution and uniform distribution of the DCD in the molten ureaprior to the granulation step. A convenient point for the addition ofDCD to urea in a urea production plant is before or between anyevaporation steps used to reduce the water content of the urea. The NBPTand UFP particle composition, however, may be introduced into the moltenurea just prior to the granulation or prilling step with only sufficientretention time in the melt to allow for uniform distribution of the NBPTin the melt. In one group of embodiments, the retention time of the meltbetween the point of the NBPT and UFP particle composition addition andthe granulation step is less than 5 minutes, or less than 1 minute.

After the NBPT and UFP particle composition is combined with the urea,the granules may be sized. In one group of embodiments, granules whichpass through a 4 mesh Tyler Series sieve (about 4.76 millimeters) andstay on a 20 mesh Tyler Series sieve (about 0.84 millimeters) areretained as product. The undersized particles may be recycled and theoversized particles may be ground and/or recycled.

The present invention also provides an improved fluid urea-ammoniumnitrate (UAN) fertilizer composition containing the NBPT and UFPparticle composition. Specifically, the improved fluid fertilizercomposition of this invention is comprised primarily of an aqueoussolution of urea, ammonium nitrate, the NBPT and UFP particlecomposition, and optionally dicyandiamide (DCD).

The urea content of the composition of this invention is between about24% and about 32% by weight, or about 26% to about 32% by weight; theammonium nitrate content of the composition is about 34% to about 42% byweight, or about 36% to about 42% by weight; the NBPT content of thecomposition is about 0.01% to about 0.4% by weight, or about 0.02% toabout 0.3% by weight; and the DCD accounts for about 0% to about 2.0% byweight of the composition, and may account for about 0.03% to about 1.5%by weight of the composition. The balance of the composition consistsprimarily of water. A solvent for the NBPT as disclosed above, may alsobe present in small quantities.

In accordance with the present invention, the NBPT and UFP particlecomposition may be incorporated into the fluid fertilizer composition byadding a solid or liquid form of the NBPT and UFP particle compositiondirectly to a UAN fluid with sufficient mixing to assure that the NBPTis homogeneously distributed throughout the fluid fertilizercomposition. Both the solid and liquid forms of the NBPT and UFPparticle composition as disclosed above can be introduced into UAN usingconventional metering devices.

The amount of the NBPT and UFP particle composition in accordance withthis invention depends on the desired NBPT content of the fertilizercomposition within the ranges specified herein above and on the NBPTcontent of the concentrated NBPT solution, and can be readily calculatedby those skilled in the art.

Like the solid formulation, DCD can also be added to the UAN fluid atthis stage, rather than with the UFP particles, alone. Several methodsare available for the introduction of DCD into UAN. If available as apowder or in granular form, the DCD can be fed into UAN fluid using aconventional solids feeding device. In one group of embodiments,however, the DCD is first incorporated into a relatively small quantityof UAN fluid so as to form a slurry of DCD in UAN fluid; this slurry isthen blended with the balance of the UAN fluid in the amount needed toprovide the desired concentration of DCD within the ranges specifiedhereinabove. Regardless of the method selected to introduce the DCD intothe UAN fluid, sufficient mixing should be provided to facilitatehomogenous distribution of the DCD throughout the UAN fluid. Thehomogeneous distribution of both the NBPT and UFP particle compositionand DCD in the fluid fertilizer compositions of this invention enhancesthe performance of these compositions in terms of their ability topromote plant growth.

The order in which the NBPT and UFP particle composition and DCD areadded to the fluid fertilizer in the practice of this invention isflexible: either the NBPT and UFP particle composition or DCD may beintroduced first, or both of these components may be addedsimultaneously. However, in light of the relative instability of NBPT inaqueous solutions, solid or liquid forms of the NBPT and UFP particlecomposition may be introduced into the fluid fertilizer relatively latein production-storage-distribution sequence of the fluid fertilizer, soas to minimize the time span between the addition of the NBPT and UFPparticle composition to the fluid fertilizer and the application of thefertilizer to the soil.

The NBPT and UFP particle composition is added to the UAN solution inthe range of about 0.1 to 5.0% additive in the final product. In onegroup of embodiments, the NBPT and UFP particle composition is added inthe range of about 0.4 to 2.5% to fluid UAN or urea solution, or blendsthereof, to form a fluid fertilizer. The fluid urea-based fertilizer ofthe present invention contains from about 0.004 to 1.50% NBPT, fromabout 0 to 0.850% DCD, from about 0.030 to about 0.30% UFP particles,and from about 99.9 to 98.0% aqueous UAN. Optionally, the fertilizer cancontain up to about 0.03% silicon dioxide. The aqueous UAN contains ureaand ammonium nitrate in concentration ranges of about 15 to 50%. In onegroup of embodiments, the range is from about 25 to 40%.

The granular fertilizer composition of this invention made by themethods described herein can be used in all agricultural applications inwhich granular fertilizer compositions are currently used. Theseapplications include a very wide range of crop and turf species, tillagesystems, and fertilizer placement methods. The fertilizer granules madewith the NBPT and UFP particle composition of present invention areuseful for fertilizing a wide variety of seeds and plants, includingseeds used to grow crops for human consumption, for silage, or for otheragricultural uses. Indeed, virtually any seed or plant can be treated inaccordance with the present invention using the compositions of thepresent invention, such as cereals, vegetables, ornamentals, conifers,coffee, turf grasses, forages and fruits, including citrus. Plants thatcan be treated include grains such as barley, oats and corn, sunflower,sugar beets, rape, safflower, flax, canary grass, tomatoes, cotton seed,peanuts, soybean, wheat, rice, alfalfa, sorghum, bean, sugar cane,broccoli, cabbage and carrot.

The granular urea-based fertilizer composition of this invention can beused in all agricultural applications in which granular urea iscurrently used. These applications include a very wide range of crop andturf species, tillage systems, and fertilizer placement methods. Mostnotably, the fertilizer composition of this invention can be applied toa field crop, such as corn or wheat, in a single surface application andwill nevertheless supply sufficient nitrogen to the plants throughouttheir growth and maturing cycles. The fertilizer composition of thisinvention is capable of supplying the nitrogen nutrient with greaterefficiency than any previously known fertilizer composition. Thecomposition increases the nitrogen uptake by plants, enhances cropyields, and minimizes the loss of both ammonium nitrogen and nitratenitrogen from the soil.

The rate at which the fertilizer composition of this invention isapplied to the soil may be identical to the rate at which urea iscurrently used for a given application, with the expectation of a highercrop yield in the case of the composition of this invention.Alternately, the composition of this invention may be applied to thesoil at lower rates than is the case for urea and still providecomparable crop yields, but with a much lower potential for nitrogenloss to the environment. It is of interest to illustrate the quantitiesof NBPT and DCD introduced into the soil when a given composition ofthis invention is applied as a fertilizer. For example, assuming thatthe composition is applied to the soil at a rate of 100 pounds per acreand that it contains 0.1% NBPT and 1% DCD, it can be readily calculatedthat the rates of NBPT and DCD application are 0.1 and 1.0 pounds peracre, respectively.

The UAN-based fluid fertilizer composition of this invention can be usedin all agricultural applications in which UAN is currently used. Theseapplications include a very wide range of crop and turf species, tillagesystems, and fertilizer placement methods.

The UAN-based fertilizer composition of this invention can be used inall agricultural applications in which UAN is currently used. Theseapplications include a very wide range of crop and turf species, tillagesystems, and fertilizer placement methods. The fertilizer composition ofthis invention can be applied to a field crop, such as corn or wheat, ina single surface application and will nevertheless supply sufficientnitrogen to the plants throughout their growth and maturing cycles.Moreover, the fluid fertilizer composition of this invention suppliesnitrogen nutrient to crop plants with greater efficiency than anypreviously known fluid fertilizer composition. The composition increasesthe nitrogen uptake by plants, enhances crop yields, and minimizes theloss of both ammonium nitrogen and nitrate nitrogen from the soil.

The rate at which the fertilizer composition of this invention isapplied to the soil may be identical to the rate at which UAN iscurrently used for a given application, with the expectation of a highercrop yield in the case of the composition of this invention.Alternately, the composition of this invention may be applied to thesoil at lower rates than is the case for UAN and still providecomparable crop yields, but with a much lower potential for nitrogenloss to the environment. It is of interest to illustrate the quantitiesof NBPT and DCD introduced into the soil when a given composition ofthis invention is applied as a fertilizer. For example, assuming thatthe composition is applied to the soil at a rate of 200 pounds per acreand that it contains 0.05% NBPT and 0.5% DCD, it can be readilycalculated that the rates of NBPT and DCD application are 0.1 and 1.0pounds per acre, respectively.

The following examples are intended to illustrate, but not limit, themethods and compositions of the invention. All percentages are by weightunless otherwise indicated.

Example 1: Spray-Dried Substantially Spherical UFP Particles

A urea-formaldehyde (UF) dispersion, suitable for producingsubstantially spherical UFP particles used in the present invention, isprepared as follows. Water (32.3 parts by weight) and a 50% aqueoussolution of formaldehyde (31.8 parts by weight) were added to a reactionvessel equipped with vacuum reflux, a heater and a mixer. Whileadjusting the temperature of the agitated aqueous mixture to 100° F.,its pH is also adjusted to about 7.0 (6.8 to 7.2) using either 50%caustic (NaOH), or 35% sulfuric acid, as needed. Once the aqueousmixture was heated to 100° F. (about 38° C.), 31.8 parts by weight ofprilled urea also was added and mixing was continued. The temperature ofthe agitated aqueous mixture then was increased to 120° F. (about 50°C.) and held for a time (usually about 15 minutes) sufficient todissolve the urea. While maintaining the temperature of the agitatedmixture at 120° F. (about 50° C.), the pH is adjusted to within therange of 8.0 to 8.4, again using either 50% caustic (NaOH), or 35%sulfuric acid as needed. Using, as appropriate, a combination of thereaction exotherm and external heating, the reaction mixture was heatedto a temperature of 158° F. and the temperature is controlled usingvacuum reflux. The pH of the mixture was adjusted, as needed, to about7.8 to 8.2, using either 50% caustic (NaOH), or 35% sulfuric acid. Theagitated mixture was held at a temperature of about 158° F. (70° C.) forabout 30 minutes and the pH was adjusted, as needed, to about 7.8 to8.2, using either 50% caustic (NaOH), or 35% sulfuric acid so that thereactants formed methylol ureas. While continuing agitation, the aqueousmixture was cooled to about 105° F. (about 40° C.) and a dispersant (onepart by weight of DAXAD 19) was added while the batch was cooled. Uponreaching 105° F. (about 40° C.), the batch was placed under full vacuum.While maintaining full vacuum and applying cooling to the agitatedbatch, the pH of the aqueous mixture was adjusted, as quickly aspossible, to a pH of about 3.3 to 3.5, using 35% sulfuric acid, at whichpoint the batch may exotherm to a temperature of above 175° F. (about80° C.) before the exotherm subsides. This procedure caused rapidcondensation of the methylol ureas to a solid network polymer. Aftercompleting the pH adjustment, the temperature of the aqueous mixture wascooled to 105° F. (about 40° C.) as quickly as possible while it washeld for 20 minutes. Following the 20 minute holding period, the pH ofthe aqueous mixture was adjusted to 6.5 to 7.5, using either 50% caustic(NaOH), or 35% sulfuric acid, as needed, and then was discharged tostorage. The UFP dispersion at about 38 weight percent solids wasagitated during its storage.

The dispersion above can then be spray dried to produce UF polymerparticles. A Niro P6 spray dryer can be fed with 15 pounds per hour ofthe dispersion of Example 1. The spray dryer receives an inlet gasstream at a flow rate of about 415 standard cubic feet per minute and atemperature of 330-340° F. (165-170° C.). The outlet temperature of thespray dryer was measured as 75-95° F. (25-35° C.). The recovered UFpolymer particle product (at about 1 wt. % moisture) had particlediameter distributed from 10 to 80 microns, with a number averagediameter of 30 microns.

Alternative Example 1: Spray-Dried UFP

Using a Niro industrial-sized spray dryer (ON 030-5051), a UF polymerdispersion made in accordance with Example 1 having about a 38 wt. %solids content, at a temperature of 28° C. and at a feed rate of 100lbs/minute was spray-dried with the atomizer wheel operating at 13,000RPMs. Air, at a flow rate of 49,400 standard cubic feet per minute andat a temperature of 186° C. was delivered to the spray dryer. The outletair temperature was measured as 88° C. Spray-dried UF polymer particleswere recovered from the spray dryer.

Alternative Example 2: Spray-Dried UFP

A UF polymer dispersion made in accordance with Example 1 using 45.27wt. % water 25.7 wt. % UFC 85. While adjusting the temperature of theagitated aqueous mixture to about 30° C., its pH is also adjusted fromabout 6.7 to 7.3 using either 50% caustic (NaOH), or 35% sulfuric acid,as needed. Once the aqueous mixture was heated to about 30° C., 24.423wt. % prilled urea also was added and mixing was continued. Thetemperature of the agitated aqueous mixture then was increased to about50° C. and held for a time (usually about 15 minutes) sufficient todissolve the urea. While maintaining the temperature of the agitatedmixture at about 50° C., the pH is adjusted to within the range of 8.0to 9.0, again using either 50% caustic (NaOH), or 35% sulfuric acid asneeded. Using, as appropriate, a combination of the reaction exothermand external heating, the reaction mixture was heated to a temperatureof about 70° C. and the temperature is controlled using vacuum reflux.The pH of the mixture was adjusted, as needed, to about 7.8 to 8.2,using either 50% caustic (NaOH), or 35% sulfuric acid. The agitatedmixture was held at a temperature of about 70° C. for about 30 minutesand the pH was adjusted, as needed, to about 7.8 to 8.2, using either50% caustic (NaOH), or 35% sulfuric acid so that the reactants formedmethylol ureas. While continuing agitation, the aqueous mixture wascooled to about 40° C. and a dispersant (one part by weight of DAXAD 19)was added while the batch was cooled. Upon reaching about 40° C., thebatch was placed under full vacuum. While maintaining full vacuum andapplying cooling to the agitated batch, the pH of the aqueous mixturewas adjusted, as quickly as possible, to a pH of about 3.1 to 3.5, 20%ammonium sulfate, at which point the batch may exotherm to a temperatureof above about 80° C. before the exotherm subsides. This procedurecaused rapid condensation of the methylol ureas to a solid networkpolymer. After completing the pH adjustment, the temperature of theaqueous mixture was cooled to about 40° C. as quickly as possible whileit was held for 20 minutes. Following the 20 minute holding period, thepH of the aqueous mixture was adjusted to 6.5 to 7.5, using 20% ammoniumsulfate, as needed, and then was discharged to storage. The UFPdispersion at about 38 weight percent solids was agitated during itsstorage. This material was spray dried as above.

Comparative Example 3: PERGOPAK® M with NBPT (N-n-butylthiophosphoricTriamide) from Albemarle Corp. with and without Mineral Oil

A sufficient quantity of WFE bottoms (about 83% NBPT available fromAlbemarle® Corporation) is sprayed onto PERGOPAK® M, a urea formaldehydepolymer commercially available from the Albemarle® Corporation, to yielda precursor powder containing about 62 wt. % NBPT. 2 wt. % of a dye(e.g. FD & C blue #1). The NBPT solution is blended into the PERGOPAK® Mcomposition at 50° C. over a 30 minute period. The mixture is stirredfor an additional 120 minutes to break up lumps until a uniform mix isachieved as indicated by the distribution of the dye. These steps can berepeated until sufficient NBPT solution has been loaded. Othercomponents, such as DCD could also be blended during this process. Afterthe addition is complete, 1% by weight mineral oil is optionally addedto reduce dust. After this addition is complete the mixture is stirredfor an additional 60 minutes to break up lumps. The mixture is allowedto air dry. The final weight of the PERGOPAK® M loaded with the NBPT isdetermined to be 100 g of as a compactable solid containing someagglomerates.

Alternative Comparative Example 4: PERGOPAK® M with NBPT from China withand without Mineral Oil

A 50% by weight solution of NBPT (available from Chinese source)solution in N-alkyl 2-pyrrolidone was added to 37 grams of PERGOPAK® M,a urea formaldehyde polymer commercially available from the Albemarle®Corporation, and 2 grams of a dye (e.g. FD & C blue #1). The NBPTsolution was blended into the PERGOPAK® M at 25° C. over a 1 minuteperiod. The mixture was stirred for an additional 14 minutes to break uplumps until a uniform mix was achieved as indicated by the distributionof the dye. These steps were repeated until sufficient NBPT solution hadbeen loaded. Other components, such as DCD could also be blended duringthis process. After the addition was complete 1% by weight mineral oilwas optionally added to reduce dust. After this addition was completethe mixture was stirred for an additional 0 minutes to break up lumps.The mixture was allowed to air dry. The final weight of the PERGOPAK® Mloaded with the NBPT was determined to be 37 g (out of a total of 100 g)of as a compactable solid containing some agglomerates.

Example 5: NITAMIN36S with NBPT Without Mineral Oil

A blend of NBPT (recrystallized or not recrystallized), Nitamin 36S UFpowder, and green dye were made. The blends were made in a 35 cubic footribbon blender (Magnablend) which ran at approximately 16 rpm. Mineraloil was eliminated from the formulation because it reduced flow inPERGOPAK M formulations and the present formulation had reduced dustwhen compared to the PERGOPAK M formulation with oil. Any clumps of NBPTthat were not incorporated into the Nitamin 36S UF powder wereoptionally removed from the final product via screening or broken up andreblended. The amount of moisture, the range of NBPT loading levelsamongst particles, dust (tapped bulk density) and powder flow weremeasured for each batch by the running them through a vibrating funnel.The data is shown in the table below, where the data is an average offour batches:

Dry Flow Amount NBPT Tapped Funnel in Drum Moisture loading level BulkMethod Composition (lbs) (%) range Density (sec) Comparative 150 2.73 6026.8 Did Not Example 3 Flow Alternative 110 5.02 60 16.0 31.3Comparative Example 4 Example 5 200 1.69 60 31.1  4.6

This data demonstrates that the flow of the formulation of the presentinvention using NITAMIN 36S was dramatically better than that usingPERGOPAK M. This formulation allowed for the formation of a productwithout the use of mineral oil. The powder flowed freely from theblender into the drums and bags. The formulation with PERGOPAK M, wouldnot flow through the funnel at all.

As the data shows the compositions of this invention (Example 5) had amore uniform loading level and more efficient loading process, improvedflow, and reduced dust (increased bulk density).

Example 6: Comparative Examples with DCD

A blend of 6.53% NBPT, DCD, UFP and dye were made as in EXAMPLE 5, usingthe formulations in the table below:

Composition Example 6A Example 6B NBPT/UFP* 12.56 (in NMP) 10.89 DCD 8181 PERGOPAK M2 6.4 0 NITAMIN 36S 0 8.07 DYE 0.04 0.04Example 6A uses PERGOPAK M2 as UFP with NBPT, Example 6B uses Nitamin36S as UFP with NBPT. The additional amount of Nitamin 36S in Example 6Bis optional. The primary advantage in Example 6B is that the NBPT isadded to this formulation without the use of any solvents. Therefore,the final product is solvent-free. Formulation 6A uses a solvent. Theamount of moisture, the range of NBPT loading levels amongst particles,dust (tapped bulk density) and powder flow were measured for each batchby the running them through a vibrating funnel. The moisture can bevaried to some degree by the amount of heat put on the oven. The data isshown in the table below, where the data is an average of four batches:

Amount NBPT Tapped 4-minute in Drum Moisture loading level Bulksolubility Composition (lbs) (%) range Density test Comparative 15004.8% 6.5% 42.1 Passed Example 6A Example 6B 1500 0-4 5.8-7 36-43 Passed

This data demonstrates that the moisture content and bulk density of theformulation of the present invention using NITAMIN 36S was dramaticallybetter than that using PERGOPAK M.

Example 7: Granular Urea Formulation with Formulation of Example 5

As a first step, a 2000 g. batch of NBPT/UFP solution of Example 5 ispumped at a rate equivalent to 3 pounds of NBPT/UFP per 1997 pounds ofurea into a 60 ton/hour stream of molten urea passing through a pipeleading from the last stage of urea evaporation directly to the ureagranulation apparatus in a urea production facility. The temperature ofthe molten urea at the point at which the NBPT/UFP solution is injectedis about 275° F. Although the retention time of the urea stream betweenthe point at which the concentrated NBPT/UFP solution is injected andthe urea granulation apparatus is only in the order of 20 seconds, thedegree of turbulence in the stream of molten urea assures thoroughmixing and homogenous distribution of the concentrated NBPT/UFP solutionin the molten urea.

Example 8: Granular Urea Formulation with Solid Formulation of NBPT andNitamin 36S

This example illustrates the incorporation of the composition of Example5 into a homogenous urea-based granular fertilizer composition. 1997pounds of granulated urea is treated with 3 pounds of the solidcomposition of Example 5. The composition of Example 5 and urea aremixed in a blender until the fertilizer mixture is observed to flowfreely. The urea-based fertilizer is used directly or is stored.

Example 9: Liquid Urea Formulation with Solid Formulation of NBPT andNitamin 36S

This example illustrates the method of this invention for theincorporation of the NBPT/NITAMIN 36S composition into a fluidurea-containing fertilizer composition. The formulation of Example 5 wasadded at a rate equivalent to 2 pounds of NBPT/UFP per 1998 pounds ofUAN solution into a 50 ton/hour stream of UAN solution containing 30%urea and 40% ammonium nitrate and approximately 10 pounds per ton DCD.

Example 10: Liquid Urea Formulation with Liquid Formulation of NBPT andNitamin 36S

This example illustrates the method of this invention for theincorporation of the NBPT/NITAMIN 36S composition into a fluidurea-containing fertilizer composition. The formulation of Example 5 wasadded at a rate equivalent to 2 pounds of NBPT/UFP per 1998 pounds ofUAN solution into a 50 ton/hour stream of UAN solution containing 30%urea and 40% ammonium nitrate and approximately 10 pounds per ton DCD.Said stream of UAN solution was being transferred from a liquid storagetank into liquid rail cars. Although the retention time of the UANsolution between the point near the liquid storage tank at which theconcentrated NBPT/UFP solution was injected into the UAN solution andthe point at which the solution was discharged into the rail car wasonly in the order of 40 seconds, the degree of turbulence in the streamof UAN solution assured thorough mixing and homogenous distribution ofthe concentrated NBPT/UFP solution in the UAN solution. A set of railcars was filled in this manner with a total of about 1400 tons of UANsolution containing about 0.1% NBPT.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, one of skill in the art will appreciate that certainchanges and modifications may be practiced within the scope of theappended claims. In addition, each reference provided herein isincorporated by reference in its entirety to the same extent as if eachreference was individually incorporated by reference. Where a conflictexists between the instant application and a reference provided herein,the instant application shall dominate.

The invention claimed is:
 1. A composition comprising a combination ofsubstantially solid pieces of N-(n-butyl) thiophosphoric triamide (NBPT)and urea-formaldehyde polymer (UFP) particles, wherein the pieces ofNBPT and the UFP particles are substantially adhered together.
 2. Thecomposition according to claim 1, wherein the UFP particles are adheredto outer surfaces of the pieces of NBPT.
 3. The composition according toclaim 1, wherein the UFP particles are coating the pieces of NBPT. 4.The composition according to claim 1, wherein the composition comprisesabout 30% to about 70% by weight of the pieces of NBPT and about 70% toabout 30% by weight of the UFP particles based on the total weight ofthe composition.
 5. The composition according to claim 1, wherein thecomposition further comprises a nitrification inhibitor.
 6. Thecomposition according to claim 3, wherein the composition furthercomprises a nitrification inhibitor selected from the group consistingof: dicyandiamide (DCD); 2-chloro-6-trichloromethylpyridine(nitrapyrin); 3,4-dimethylpyrazole phosphate (DMPP); 3-methylpyrazole(MP); 1-H-1,2,4-triazole (TZ); 3-methylpyrazole-1-carboxamide (CMP);4-amino-1,2,4-triazole (AT, ATC); 3-amino-1,2,4-triazole;2-cyanimino-4-hydroxy-6-methylpyrimidine (CP); 2-ethylpyridine; ammoniumthiosulfate (ATS); sodium thiosulfate (ST); thiophosphoryl triamide;thiourea (TU); guanylthiourea (GTU); ammonium polycarboxylate; ethyleneurea; hydroquinone; phenylacetylene; phenylphosphoro diamidate;neemcake; calcium carbide; 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol(etridiazol, terraole); 2-amino-4-chloro-6-methylpyrimidine (AM);1-mercapto-1,2,4-triazole (MT); 2-mercaptobenzothiazole (MBT);2-sulfanilamidothiazole (ST); 5-amino-1,2,4-thiasiazole;2,4-diamino-6-trichloromethyl-s-triazine (CL-1580); N-2,5-dichlorophenylsuccinanilic acid (DCS); nitroaniline; chloroaniline; salts thereof; andcombinations thereof.
 7. The composition according to claim 5, whereinthe nitrification inhibitor is DCD.
 8. The composition according toclaim 6, wherein the nitrification inhibitor is nitrapyrin.
 9. Thecomposition according to claim 6, wherein the composition comprisesabout 1% to about 60% by weight of the pieces of NBPT, about 1% to about35% by weight of the UFP particles, and about 5% to about 98% by weightof the nitrification inhibitor based on the total weight of thecomposition.
 10. The composition according to claim 1, wherein thecomposition further comprises a component selected from the groupconsisting of a conditioner, a dye, xanthan gum, and combinationsthereof.
 11. The composition according to claim 10, wherein thecomposition comprises a conditioner selected from the group consistingof tricalcium phosphate, sodium bicarbonate, sodium ferricyanide,potassium ferricyanide, bone phosphate, sodium silicate, silicondioxide, calcium silicate, talcum powder, bentonite, calcium aluminumsilicate, stearic acid, sodium aluminosilicate, polyacrylate powder, andcombinations thereof.
 12. The composition according to claim 3, whereinthe UFP particles have an average particle diameter of about 0.05microns to about 250 microns.
 13. The composition according to claim 12,wherein the UFP particles have an average particle diameter of about 0.1microns to about 150 microns.
 14. The composition according to claim 12,wherein the UFP particles have a size distribution such that about 1% toabout 20% by weight of the UFP particles have an average particlediameter of about 0.05 microns to about 5 microns.
 15. The compositionaccording to claim 12, wherein about 1% to about 20% by weight of theUFP particles have an average particle diameter of about 0.1 microns toabout 1 micron, and about 80% to about 99% by weight of the UFPparticles have an average particle diameter that is greater than 1micron.
 16. The composition according to claim 1, wherein thecomposition further comprises urea.
 17. The composition according toclaim 16, wherein the composition comprises about 90% to about 99% byweight of urea and about 0.02 to about 0.5% by weight of the pieces ofNBPT based upon the overall weight of the composition.
 18. Thecomposition according to claim 16, wherein the composition furthercomprises a nitrification inhibitor.
 19. The composition according toclaim 1, wherein the composition is in the form of a granular fertilizersuch that the granules of the fertilizer have an average diameter ofabout 0.8 to about 4.8 millimeters.
 20. The composition according toclaim 1, wherein the composition further comprises an aqueous solutionof urea ammonium nitrate (UAN).
 21. The composition according to claim1, wherein the composition comprises about 24% to about 32% by weight ofurea, about 34% to about 42% by weight of ammonium nitrate, and about0.01% to about 0.4% by weight of the pieces of NBPT based on the overallweight of the composition.
 22. The composition according to claim 21,wherein the composition further comprises a nitrification inhibitor. 23.The composition according to claim 22, wherein the composition comprisesabout 0.01% to about 2.0% by weight of the nitrification inhibitor basedon the overall weight of the composition.
 24. The composition accordingto claim 3, wherein the pieces of NBPT comprise crystalline NBPT. 25.The composition according to claim 3, wherein the pieces of NBPTcomprise amorphous NBPT.
 26. The composition according to claim 18,wherein the nitrification inhibitor is dicyandiamide (DCD).
 27. Thecomposition according to claim 3, wherein the composition furthercomprises urea and a nitrification inhibitor selected from the groupconsisting of: dicyandiamide (DCD); 2-chloro-6-trichloromethylpyridine(nitrapyrin); 3,4-dimethylpyrazole phosphate (DMPP); 3-methylpyrazole(MP); 1-H-1,2,4-triazole (TZ); 3-methylpyrazole-1-carboxamide (CMP);4-amino-1,2,4-triazole (AT, ATC); 3-amino-1,2,4-triazole;2-cyanimino-4-hydroxy-6-methylpyrimidine (CP); 2-ethylpyridine; ammoniumthiosulfate (ATS); sodium thiosulfate (ST); thiophosphoryl triamide;thiourea (TU); guanylthiourea (GTU); ammonium polycarboxylate; ethyleneurea; hydroquinone; phenylacetylene; phenylphosphoro diamidate;neemcake; calcium carbide; 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol(etridiazol, terraole); 2-amino-4-chloro-6-methylpyrimidine (AM);1-mercapto-1,2,4-triazole (MT); 2-mercaptobenzothiazole (MBT);2-sulfanilamidothiazole (ST); 5-amino-1,2,4-thiasiazole;2,4-diamino-6-trichloromethyl-s-triazine (CL-1580); N-2,5-dichlorophenylsuccinanilic acid (DCS); nitroaniline; chloroaniline; salts thereof; andcombinations thereof.
 28. The composition according to claim 22, whereinthe nitrification inhibitor is dicyandiamide (DCD).
 29. The compositionaccording to claim 3, wherein the composition comprises about 24% toabout 32% by weight of urea, about 34% to about 42% by weight ofammonium nitrate, and about 0.01% to about 0.4% by weight of the piecesof NBPT based on the overall weight of the composition, and wherein thecomposition further comprises urea and a nitrification inhibitorselected from the group consisting of: dicyandiamide (DCD);2-chloro-6-trichloromethylpyridine (nitrapyrin); 3,4-dimethylpyrazolephosphate (DMPP); 3-methylpyrazole (MP); 1-H-1,2,4-triazole (TZ);3-methylpyrazole-1-carboxamide (CMP); 4-amino-1,2,4-triazole (AT, ATC);3-amino-1,2,4-triazole; 2-cyanimino-4-hydroxy-6-methylpyrimidine (CP);2-ethylpyridine; ammonium thiosulfate (ATS); sodium thiosulfate (ST);thiophosphoryl triamide; thiourea (TU); guanylthiourea (GTU); ammoniumpolycarboxylate; ethylene urea; hydroquinone; phenylacetylene;phenylphosphoro diamidate; neemcake; calcium carbide;5-ethoxy-3-trichloromethyl-1,2,4-thiadiazol (etridiazol, terraole);2-amino-4-chloro-6-methylpyrimidine (AM); 1-mercapto-1,2,4-triazole(MT); 2-mercaptobenzothiazole (MBT); 2-sulfanilamidothiazole (ST);5-amino-1,2,4-thiasiazole; 2,4-diamino-6-trichloromethyl-s-triazine(CL-1580); N-2,5-dichlorophenyl succinanilic acid (DCS); nitroaniline;chloroaniline; salts thereof; and combinations thereof.
 30. A method offorming an agricultural composition, the method comprising blendingsubstantially solid pieces of N-(n-butyl) thiophosphoric triamide (NBPT)with urea-formaldehyde polymer (UFP) particles under conditions suchthat the UFP particles become substantially adhered to outer surfaces ofthe pieces of NBPT.